JP2013185121A - Method for producing protective film and protective film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for simply and inexpensively producing a protective film with which an image can be favorably visible even when visually recognizing it through a pair of polarizing sunglasses, and panel scattering or scratch formation can be prevented.SOLUTION: There is provided a method for producing a protective film to be pasted to a transparent panel in an image display device having an image display module of which emitted light is linearly-polarized light, and the transparent panel, where the protective film has a film substrate layer comprising a biaxially oriented polyethylene-based resin film, and the method includes a step of obtaining a protective film of substantially square shape by punching an original film of the protective film, and the punching processing to the substantially square shape is carried out such that an angle θ1 between a polarizing axis of the linearly-polarized light emitted from the image display part and one orientation axis of a molecule in the film substrate layer, and an angle θ2 between the polarizing axis of the linearly-polarized light emitted from the image display part and the other orientation axis of a molecule in the film substrate layer become 20-70°.

Description

  In an image display device having an image display module in which light emitted from an image display unit is linearly polarized light, and a transparent panel provided on an upper part of the image display module, a protective film to be attached to at least one surface of the transparent panel, and It relates to a manufacturing method.

  Image display devices such as a liquid crystal display (LCD) and an organic EL display are used in a wide range of fields including personal computers. In particular, portable electronic terminals such as electronic notebooks, mobile phones, smartphones, portable audio players, PDAs, and tablet terminals are becoming increasingly smaller and thinner in recent years, and there is also a demand for higher definition due to support for video playback functions and the like. It is high. As such an image display device, for example, an image display module such as an LCD module or an organic EL module is included in the configuration, and a transparent panel for protecting the image display module is provided above the image display module. An image display device is used. In recent years, glass panels are often used as the above transparent panels for the purpose of improving the design and texture of electronic devices, and transparent panels are used to prevent damage to glass and to prevent glass from scattering when broken. (See, for example, Patent Document 1).

  In an image display device such as an LCD, the emitted light is often linearly polarized for convenience of the module configuration. Therefore, when viewing an image using polarized sunglasses or the like, there is a problem that the emitted linearly polarized light is orthogonal to the polarized sunglasses and the image cannot be seen.

  As means for solving this problem, there is a method of converting linearly polarized light into circularly polarized light by attaching a retardation film or the like in an image display device (see Patent Document 2). However, in an image display device having an image display module in which the light emitted from the image display unit is linearly polarized light, the image display module already has a polarizing plate and a polarizing film. In the case where a film is provided, there is a problem that the decrease in light transmittance is increased by the other number of films. Further, the retardation film is generally expensive, and there is a problem that the production cost increases.

JP 2010-275385 A JP 2004-268835 A

  The problem to be solved by the present invention is to provide a method for easily and inexpensively manufacturing a protective film that allows a user to visually recognize an image even when viewed through polarized sunglasses and prevent panel scattering and scratches. There is to do.

  In the present invention, in an image display device having an image display module in which light emitted from the image display unit is linearly polarized light and a transparent panel provided on the image display module, the image display unit is attached to at least one surface of the transparent panel. A method for producing a protective film, wherein the protective film is a protective film having a film base layer composed of a biaxially stretched polyethylene resin film, and the raw film of the protective film is cut and processed. A step of obtaining a rectangular protective film, and the punching into the substantially rectangular shape is emitted from the image display unit when a transparent panel having a protective film attached to the top of the image display module is provided. Angle θ1 formed by the polarization axis of the linearly polarized light and one of the orientation axes of the molecules of the film base material layer, and emitted from the image display unit The method for producing a protective film angle θ2 formed between the other orientation axis of the molecules of the the polarization axis of the linear polarizing film base layer is punched to be a 20 to 70 °, to solve the above problems.

  According to the production method of the present invention, a general-purpose biaxially stretched polyethylene resin film can be used as a substrate, and a protective film having a desired optical axis can be obtained from the entire area of the protective film. For this reason, according to the manufacturing method of the present invention, when the emitted light is used for the transparent panel of the linearly polarized image display device, the image can be satisfactorily viewed through the polarized sunglasses, and the panel is preferably scattered or damaged. The protective film which can be prevented can be manufactured easily and inexpensively.

It is the schematic which shows an example of substantially square shapes, such as an image display part in this invention. It is the schematic which shows the polarization direction of the linearly polarized light of the image display apparatus in this invention. It is the schematic which shows angle (theta) 1 and (theta) 2 which the orientation axis direction of the molecule | numerator of the protective film obtained by this invention and the polarization direction of the linearly polarized light in an image display apparatus make. It is the schematic which shows the orientation axis | shaft of the width direction of the biaxially stretched polyethylene-type resin film base material used for the protective film original fabric in this invention. It is the schematic which shows angle (phi) which the horizontal axis of the image display part in this invention and the polarization axis of the linearly polarized light radiate | emitted from an image display part make. It is a conceptual diagram which shows angle (gamma) which the width direction of the biaxially stretched polyethylene-type resin film of the base material of the protective film in this invention, and the orientation axis | shaft of the width direction in a polyethylene-type resin film make. It is a conceptual diagram which shows the optimal punching process angle (alpha) of the protective film in this invention. It is the schematic of evaluation of the image visibility in the Example of this invention. It is an evaluation result of image visibility in an image display device of Example 1 of the present invention. It is an evaluation result of image visibility in an image display device of Example 3 of the present invention. It is an evaluation result of image visibility in an image display device of comparative example 1 of the present invention.

  The method for producing a protective film of the present invention includes: an image display module having an image display module in which light emitted from an image display unit is linearly polarized light; and a transparent panel provided on the image display module. The protective film is a protective film having a film base layer made of a biaxially stretched polyethylene-based resin film, and the original film of the protective film. When the transparent panel with the protective film attached to the upper part of the image display module is provided, the process of obtaining a substantially rectangular protective film is obtained. , The angle θ1 formed by the polarization axis of linearly polarized light emitted from the image display unit and one of the orientation axes of the molecules of the film base layer, and Is a manufacturing method other alignment axis and the angle θ2 of the molecules of the film substrate layer and the polarization axis of the linearly polarized light emitted from the image display unit is a punching to be 20 to 70 °.

[Image display device]
The image display apparatus in the present invention is an image display apparatus in which a transparent panel with a protective film attached is provided on the upper part of the image display module.

[Image display module]
The image display module in the present invention is not particularly limited as long as the light emitted from the image display unit is linearly polarized light, and examples thereof include an LCD module and an organic EL module. The module of the present invention also includes a module laminate in which a touch panel module or the like is provided on the upper part of these modules.

  The shape of the image display unit of the image display module is preferably a substantially square shape. The substantially square shape facilitates incorporation into various display devices, particularly small electronic terminals. In the present invention, the substantially square shape means a rectangular or square square shape (FIG. 1 (a)), and an arbitrary corner of the square shape, preferably a shape in which four corners are chamfered (FIG. 1 (b), (C)) and the like approximate to a square shape.

  As shown in FIG. 2, the polarization direction of linearly polarized light in the present invention is an image display device having a transparent panel 2 above an image display module 1 that emits linearly polarized light 3, and the transparent panel 2 is a surface layer of the image display device. When the image display surface 4 is configured, the polarization direction 5 (polarization axis) of the linearly polarized light 3 on the image display surface 4 is referred to.

  When the image display unit of the image display module has a rectangular shape, an angle ψ1 formed by the polarization direction of linearly polarized light emitted from the image display unit and the side of the image display unit is 0 to 10 °. Is desirable. Since the angle ψ1 is within this range, the polarization direction of the linearly polarized light can be easily recognized, so the angle formed by the polarization axis of the linearly polarized light emitted from the image display unit and the orientation axis of the molecules of the film base material of the protective film It becomes easy to adjust θ1 and θ2.

  It is also desirable that the angle ψ2 formed by the polarization direction of the linearly polarized light emitted from the image display unit and the base of the image display unit is 0 to 10 °. In this range as well, the polarization direction of linearly polarized light can be easily recognized, making it easy to adjust the angles θ1 and θ2.

[Transparent panel]
Although the transparent panel in this invention is not specifically limited, As a panel generally used, there exist a glass plate, (meth) acrylic resin, polycarbonate resin, polyethylene terephthalate resin, etc. Particularly in recent years, it is preferable to use a glass panel for the purpose of improving the design and texture of an electronic device.

  The glass panel is preferably a tempered glass plate. Examples of the tempered glass include tempered glass manufactured by HOYA, Gorilla glass manufactured by Corning, and IG3 manufactured by Ishizuka Glass. Examples of a method for strengthening the glass plate include a physical strengthening method and a chemical strengthening method. In particular, chemical strengthening methods include an ion exchange method and an air cooling strengthening method. Examples of the material of the glass plate include float glass, alkali glass, and alkali-free glass.

  In addition, the transparent panel includes a case where an electrode layer or the like is patterned and has a function of a touch sensor or the like.

  A decorative part may be provided in a transparent panel. The decoration portion includes characters and figures that are visually recognized around the screen display portion of the mobile electronic terminal, or a black or white background provided on the back of these. These decorative portions are preferable because they can be easily provided by printing on a transparent panel. The printing method and printing ink are not particularly limited, and a commonly used printing method such as silk printing or pad printing or printing ink can be used.

[Protective film]
The protective film in this invention is a protective film which has a film base material layer which consists of a biaxially stretched polyethylene-type resin film. The film may be a film using a biaxially stretched polyethylene resin film as the base material layer, but preferably has a pressure-sensitive adhesive layer on one side or both sides. By having the pressure-sensitive adhesive layer, it can be easily attached to the transparent panel of the image display device.

  The protective film may have a hard coat layer on one side or both sides of the film substrate.

  The thickness of the protective film used in the present invention and the total thickness thereof are 300 μm or less, preferably 50 to 300 μm, and more preferably 100 to 250 μm. By making the thickness within this range, it becomes easy to achieve both the prevention of scratches on the panel, durability against impacts, and punching accuracy.

  The protective film of the present invention preferably has high transparency from the viewpoint of use in an image display device.

  The total light transmittance in the visible light wavelength region of the protective film of the present invention is preferably 85% or more, more preferably 90% or more, haze of 1.0 or less, particularly preferably 0.5 or less. When the total light transmittance and the haze are within the above ranges, the protective film has high transparency, and the display screen is easily refined.

[Base material layer]
The base material layer of the protective film according to the present invention is a biaxially stretched polyethylene resin film. As the biaxially stretched polyethylene resin film, PET (polyethylene terephthalate), PEN (polyethylene naphthalate), or the like can be used.

  The thickness of the polyethylene resin film is preferably 25 to 200 μm, more preferably 50 to 150 μm, and most preferably 75 to 125 μm. By making the thickness within this range, it becomes easy to achieve both prevention of damage to the panel and durability against impacts and reduction in thickness of the image display device.

[Adhesive layer]
As the pressure-sensitive adhesive layer, it is preferable to use a pressure-sensitive adhesive layer having a thickness of 5 to 50 μm. In the present invention, by setting the thickness of the pressure-sensitive adhesive layer to the thickness, sufficient adhesive strength with the object to be adhered can be expressed, and even when stress concentration occurs on the surface of the protective adhesive film, the protective adhesive Since the elastic modulus of the entire film can be kept high, it is easy to prevent damage to the panel.

  For the pressure-sensitive adhesive used in the pressure-sensitive adhesive layer, known acrylic, rubber-based, and silicone-based pressure-sensitive resins can be used. Among them, an acrylic copolymer containing a (meth) acrylic acid ester monomer having an alkyl group having 2 to 14 carbon atoms as a main monomer component is from the viewpoint of transparency, light resistance and heat resistance. preferable.

  Specific examples of the (meth) acrylic acid ester monomer having 2 to 14 carbon atoms include ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, sec-butyl acrylate, t-butyl acrylate, n -Hexyl acrylate, cyclohexyl acrylate, n-octyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, isononyl acrylate, isodecyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate , Sec-butyl methacrylate, t-butyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, - octyl methacrylate, isooctyl methacrylate, 2-ethylhexyl methacrylate, isononyl methacrylate, isodecyl methacrylate, lauryl methacrylate and the like.

  Among them, a methacrylic acid alkyl ester monomer having an alkyl side chain having 4 to 9 carbon atoms or an acrylic acid alkyl ester monomer having an alkyl side chain having 4 to 9 carbon atoms is preferable, and the carbon number is More preferred are alkyl acrylate monomers having 4 to 9 alkyl side chains. Of these, n-butyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, isononyl acrylate, and ethyl acrylate are particularly preferable. By using a (meth) acrylic acid alkyl ester having an alkyl side chain with a carbon number within the range, it is easy to ensure a suitable adhesive force.

  The content of the (meth) acrylic acid ester monomer having 2 to 14 carbon atoms in the monomer constituting the acrylic copolymer used for the pressure-sensitive adhesive layer is preferably 60% by mass or more, and 80 More preferably, it is at least mass%. It becomes easy to ensure suitable adhesive force by setting it as content of the said C2-C14 (meth) acrylic acid ester monomer in a (meth) acrylic acid ester copolymer.

  Acrylic copolymers further contain (meth) acrylic acid ester monomers and other vinyl monomers having polar groups such as hydroxyl, carboxyl and amino groups in the side chain as monomer components. It is preferable to do.

  Examples of the monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, hydroxypropyl (meth) acrylate, and caprolactone-modified (meth) acrylate. Hydroxyl group-containing (meth) acrylates such as polyethylene glycol mono (meth) acrylate and polypropylene glycol (meth) acrylate can be used, among which 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxy It is preferred to use hexyl (meth) acrylate as a copolymerization component.

  As the monomer having a carboxyl group, acrylic acid, methacrylic acid, itaconic acid, maleic acid, crotonic acid, (meth) acrylic acid dimer, ethylene oxide-modified succinic acid acrylate, etc. can be used. It is preferable to use it as a copolymerization component.

  Examples of the monomer having a nitrogen atom include N-vinyl-2-pyrrolidone, N-vinylcaprolactam, acryloylmorpholine, acrylamide, N, N-dimethylacrylamide, and 2- (perhydrophthalimido-N-yl) ethyl acrylate. An amide group-containing vinyl monomer can be used, and among these, N-vinyl-2-pyrrolidone, N-vinylcaprolactam, and acryloylmorpholine are preferably used as the copolymerization component.

  Examples of vinyl monomers having other polar groups include vinyl acetate, acrylonitrile, maleic anhydride, itaconic anhydride and the like.

  The content of the monomer having a polar group is preferably 0.1 to 20% by weight of the monomer component constituting the acrylic copolymer, more preferably 1 to 13% by weight, More preferably, it is 1.5 to 8% by weight. By containing in the said range, it is easy to adjust the cohesive force, holding force, and adhesiveness of an adhesive to a suitable range.

  The weight average molecular weight Mw of the acrylic copolymer can be measured by gel permeation chromatograph (GPC).

  Further, in order to increase the cohesive strength of the pressure-sensitive adhesive layer, it is preferable to add a crosslinking agent in the pressure-sensitive adhesive. As a crosslinking agent, an isocyanate type crosslinking agent, an epoxy type crosslinking agent, a chelate type crosslinking agent etc. are mentioned, for example. The addition amount of the crosslinking agent is preferably adjusted so that the gel fraction of the pressure-sensitive adhesive layer is 30 to 90%. A more preferable gel fraction is 50 to 85%. Among these, 60 to 80% is most preferable. It becomes easy to suppress the fall of the surface pencil hardness when a protective adhesive film is affixed on a panel as a gel fraction is 30% or more. On the other hand, when the gel fraction is 90% or less, suitable adhesiveness can be easily obtained. The gel fraction is expressed as a percentage of the original weight by measuring the weight after drying the insoluble content remaining after 24 hours of immersion in the adhesive layer after curing.

  Furthermore, in order to improve the adhesive strength of the pressure-sensitive adhesive layer, a tackifier resin may be added. The tackifying resin to be added to the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape of the present invention is an acrylic copolymer, a rosin resin such as rosin or an esterified rosin; a terpene such as a diterpene polymer or an α-pinene-phenol copolymer. Examples of such resins include: petroleum resins such as aliphatic (C5) and aromatic (C9); styrene resins, phenolic resins, xylene resins, and the like. In order to reduce the b * value of the pressure-sensitive adhesive layer after standing at 100 ° C. for 14 days to 6 or less, there are few unsaturated double bonds, esterified products of hydrogenated rosin and disproportionated rosin, aliphatic and aromatic series It is preferable to add petroleum tree etc. to the adhesive layer

  As the addition amount of the tackifier resin, when the pressure-sensitive adhesive resin is an acrylic copolymer, it is preferable to add 10 to 60 parts by weight with respect to 100 parts by weight of the acrylic copolymer. When importance is attached to adhesiveness, it is most preferable to add 20 to 50 parts by weight. Further, when the pressure-sensitive adhesive resin is a rubber-based resin, it is preferable to add 80 to 150 parts by weight of the tackifier resin with respect to 100 parts by weight of the rubber-based resin. In general, when the adhesive resin is a silicone resin, no tackifying resin is added.

  In addition to the above, known and commonly used additives can be added to the adhesive. For example, in order to improve the adhesion to glass, a silane coupling agent can be added in the range of 0.001 to 0.005. In addition, plasticizers, softeners, fillers, pigments, flame retardants, and the like can be added.

  The weight average molecular weight Mw of the acrylic copolymer used for the pressure-sensitive adhesive layer is preferably 400,000 to 1,400,000, and more preferably 600,000 to 1,200,000. When the weight average molecular weight Mw of the acrylic copolymer is within the above range, it is easy to secure a suitable adhesive force, and when a protective adhesive film is obtained, the load on the film surface can be relaxed suitably.

[Hard coat layer]
As the hard coat layer used in the present invention, a hard coat layer usually used as a protective film for an image display device or the like can be used, and any hard coat layer can be used without particular limitation as long as it can prevent scratches. As the hard coat layer, when the hard coat film is formed by laminating with the retardation film, the hard coat layer preferably has a pencil hardness of F or more, and preferably H or more. . By setting the hardness to F or higher, the ability to prevent scratches on the transparent panel can be improved.

  In addition, it is preferable that the hard coat layer has high transparency or does not contain a polarizing substance because it becomes easy to obtain suitable visibility. As the transparency of the hard coat layer, the total light transmittance of the hard coat layer is 85%, preferably 90% or more. The haze value is preferably 1.0 or less, and particularly preferably 0.5 or less.

  The hard coat agent used in the hard coat layer is not particularly limited as long as it has the above-mentioned characteristics. However, since the hard coat layer can be easily formed, a hard coat comprising an active energy ray-curable resin composition is used. An agent can be preferably used. As such an active energy ray-curable resin composition, a polyfunctional acrylate resin composition is preferable, and a urethane acrylate hard coat agent is particularly preferable.

  Among these, urethane acrylate-based hard coat agents include urethane, which is an addition reaction product of polyisocyanate (a1) and acrylate (a2) having one hydroxyl group and two or more (meth) acryloyl groups in one molecule. A hard coat agent containing an acrylate (A) can be preferably used. The urethane acrylate (A) has an α, β-unsaturation having a functional group capable of reacting with the reactive functional group in the (meth) acrylate polymer (b1) having a reactive functional group in the side chain. It is also preferred to use a polymer (B) having a (meth) acryloyl group obtained by reacting the compound (b2).

  Examples of the polyisocyanate (a1) include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 4,4′-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 4 Aromatic isocyanate compounds such as 4,4'-diphenylmethane diisocyanate; alicyclic hydrocarbons such as dicyclohexylmethane diisocyanate, isophorone diisocyanate, norbornane diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated methylenebisphenylene diisocyanate, 1,4-cyclohexane diisocyanate Compound having two bonded isocyanate groups (hereinafter abbreviated as alicyclic diisocyanate); trimethylene diisocyanate, hexamethylene diisocyanate Compounds having two isocyanate groups attached to aliphatic hydrocarbons over preparative like (hereinafter, referred to as aliphatic diisocyanates.) And the like. These polyisocyanates can be used alone or in combination of two or more.

  Of these polyisocyanates (a1), aliphatic diisocyanates or alicyclic diisocyanates are preferable, and among them, isophorone diisocyanate, norbornane diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated methylene bisphenylene diisocyanate, and hexamethylene diisocyanate are preferable. In particular, norbornane diisocyanate is most preferable.

  Examples of the acrylate (a2) having one hydroxyl group and two or more (meth) acryloyl groups in one molecule include trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta ( Examples include polyacrylates of polyhydric hydroxyl group-containing compounds such as (meth) acrylate, adducts of these polyacrylates with ε-caprolactone, adducts of these polyacrylates with alkylene oxide, epoxy acrylates, etc. Can be mentioned. These acrylates (a2) can be used alone or in combination of two or more.

  Of these acrylates (a2), an acrylate having one hydroxyl group and 3 to 5 (meth) acryloyl groups in one molecule is preferable. Examples of such acrylates include pentaerythritol triacrylate, dipentaerythritol pentaacrylate, and the like, and these are particularly preferable because a cured film having high hardness can be obtained.

  The urethane acrylate (A) used in the present invention is obtained by subjecting two components of the polyisocyanate (a1) and the acrylate (a2) to an addition reaction. The ratio of the acrylate (a2) to 1 equivalent of the isocyanate in the polyisocyanate (a1) is usually preferably 0.1 to 50, more preferably 0.1 to 10, and preferably 0.9 to 1.2 as the hydroxyl equivalent. Is more preferable. Moreover, 30-150 degreeC is preferable and, as for the reaction temperature of the said polyisocyanate (a1) and the said acrylate (a2), 50-100 degreeC is more preferable.

  The blending amount of the urethane acrylate (A) in 100 parts by weight of the resin component in the resin composition is preferably 5 to 90 parts by weight, more preferably 10 to 70 parts by weight, and even more preferably 10 to 60 parts by weight. . If the blending amount of the urethane acrylate (A) is within this range, a cured film having a sufficiently high hardness can be obtained, and there is no coating film defect, excellent surface antifouling properties, and curing shrinkage is reduced. Curling of a film having a cured coating can also be reduced.

  The molecular weight of the urethane acrylate (A) is preferably in the range of 500 to 1,500. When the molecular weight is within this range, a cured film having a sufficiently high hardness can be obtained and the curing shrinkage can be reduced, so that the curl of the film having the cured film can also be reduced.

  The blending amount of the urethane acrylate (A) in 100 parts by weight of the resin component in the resin composition is preferably 5 to 90 parts by weight, more preferably 10 to 70 parts by weight, and even more preferably 10 to 60 parts by weight. . If the blending amount of the urethane acrylate (A) is within this range, a cured film having a sufficiently high hardness can be obtained, and there is no coating film defect, excellent surface antifouling properties, and curing shrinkage is reduced. Curling of a film having a cured coating can also be reduced.

  As the reactive functional group of the (meth) acrylate polymer (b1) having a reactive functional group in the side chain used in the present invention, a hydroxyl group, a carboxyl group, an epoxy group or the like is preferable. Moreover, as a functional group which the (alpha), (beta)-unsaturated compound (b2) which can react with these reactive functional groups has, an isocyanate group, a carboxyl group, an acid halide group, a hydroxyl group, an epoxy group etc. are preferable. The (meth) acrylate polymer (b1) having a reactive functional group in the side chain was reacted with an α, β-unsaturated compound (b2) having a functional group capable of reacting with the reactive functional group. The method for producing the polymer (B) having a (meth) acryloyl group is not particularly limited and can be produced by various methods.

  The hard coat film used in the present invention can be produced by applying a hard coat agent on a film substrate and curing it.

  Examples of methods for applying a hard coating agent to a film substrate include gravure coating, roll coating, comma coating, air knife coating, kiss coating, spray coating, transfer coating, dip coating, spinner coating, wheeler coating, brush coating, and silk. Examples thereof include a solid coat using a screen, a wire bar coat, and a flow coat. Also, printing methods such as offset printing and letterpress printing may be used. Among these, gravure coating, roll coating, comma coating, air knife coating, kiss coating, wire bar coating, and flow coating are preferable because a coating film having a more constant thickness can be obtained.

  Curing of the hard coating agent may be appropriately performed according to the hard coating agent to be used, but when the active energy ray-curable resin composition is used as the hard coating agent, the activity of light, electron beam, radiation, etc. What is necessary is just to harden with an energy ray. Specific energy sources or curing devices include, for example, germicidal lamps, ultraviolet fluorescent lamps, carbon arc, xenon lamps, high pressure mercury lamps for copying, medium or high pressure mercury lamps, ultrahigh pressure mercury lamps, electrodeless lamps, metal halide lamps, natural light, etc. Or an electron beam using a scanning type or curtain type electron beam accelerator.

  Among these, ultraviolet rays are particularly preferable, and irradiation in an inert gas atmosphere such as nitrogen gas is preferable in terms of increasing the polymerization efficiency. Further, if necessary, heat may be used as an energy source and heat treatment may be performed after curing with active energy rays.

  When ultraviolet rays are used as a device for irradiating active energy rays, the light source is a low pressure mercury lamp, high pressure mercury lamp, ultra high pressure mercury lamp, metal halide lamp, electrodeless lamp (fusion lamp), chemical lamp, black light. Lamps, mercury-xenon lamps, short arc lamps, helium / cadmium lasers, argon lasers, sunlight, LEDs and the like can be mentioned. In addition, when the active energy ray-curable resin composition used in the present invention is applied to a film substrate to form a cured film, a flashing xenon-flash lamp is used. This is preferable because the influence of heat can be reduced.

[Punching]
The protective film of the present invention is obtained by punching into a substantially square shape from the original film of the protective film. The protective film is made of a biaxially stretched polyethylene resin film, and is provided with a pressure-sensitive adhesive layer or hard coat layer as necessary. It may be in various forms used.

  Although the protective film of the present invention has a substantially square shape, the substantially square shape is not limited to a rectangular or square square shape as described above, and any corner of the square shape, preferably four corners. Includes shapes approximate to square shapes such as chamfered shapes.

  The process of punching the protective film from the original fabric into a substantially square shape is the polarization of linearly polarized light emitted from the image display unit when a transparent panel with a protective film attached is provided on the top of the image display module. The angle θ1 formed by the axis and one of the alignment axes of the molecules of the film substrate layer, and the angle θ2 formed by the polarization axis of the linearly polarized light emitted from the image display unit and the other alignment axis of the molecules of the film substrate layer Is a punching process of 20 to 70 °.

  Furthermore, the angles θ1 and θ2 formed by the polarization axis of linearly polarized light emitted from the image display unit of the image display device and the molecular orientation axis of the polyethylene resin film substrate layer of the protective film are preferably 30 to 60 °. 35 to 55 ° is more preferable, and 40 to 50 ° is most preferable. By setting θ1 and θ2 in the above range, visibility from all directions can be further improved even when polarized sunglasses are used.

  Θ1 and θ2 in the substantially rectangular protective film are as shown in FIGS. 3A and 3B, and the polarization direction 5 of the linearly polarized light emitted from the image display unit of the image display module on the image display surface 4. And the angle between one orientation axis direction 6 of the substrate layer of the protective film is θ1, and the angle between the polarization direction 5 of the linearly polarized light emitted from the image display unit and the other orientation axis direction 7 is θ2. It is. Note that θ1 and θ2 are angles on the narrow angle side among the angles formed by the polarization direction and the alignment axis direction. Further, any axial direction may be used as a reference.

  The above-described punching to the angles of θ1 and θ2 is a polyethylene-based resin film stretched biaxially in the protective film according to the polarization axis of linearly polarized light emitted from the image display unit of the image display device to be applied. The punching angle is appropriately adjusted so that the orientation axis of the molecules of the base material layer becomes a desired angle after the punching.

  Since the biaxially stretched polyethylene resin film used as the base material of the protective film is manufactured by stretching in the flow direction and the width direction at the time of film production, due to the bowing phenomenon during the stretching process, The orientation axis of the molecule is shifted with respect to the flow direction and the stretching direction in the width direction. Therefore, the punching process is performed at a punching angle corresponding to the shift in the stretching direction of the orientation axes of the molecules in the polyethylene-based resin film, depending on the punching position of the original film of the protective film.

  In a general biaxially stretched polyethylene resin film, the molecular orientation axis in the width direction exists at an angle shifted by about 0 to 45 ° from the stretch direction. For this reason, the protective film original fabric using the biaxially stretched polyethylene resin film as a base material layer is subjected to a punching process by appropriately adjusting a punching angle in the width direction. A protective film having θ2 can be obtained.

  The punching process will be described in detail below with reference to the drawings when a protective film original fabric using a biaxially stretched polyethylene resin film having a misalignment angle of the orientation axis in the width direction is used as a base material layer. FIG. 4 shows an example of a raw film of a protective film using a biaxially stretched polyethylene resin film stretched in the flow direction and the width direction as a base material layer. In FIG. 4, the biaxially stretched polyethylene resin film in the original film 10 of the protective film is stretched in the stretching direction 11 in the flow direction and in the stretching direction 12 in the width direction, and with respect to the stretching direction 12 in the width direction, The molecular orientation axis 13 of the biaxially stretched polyethylene resin film has a shift angle γ from the stretch direction 12 at each position in the width direction. The molecular orientation axis 13 in the width direction is the orientation axis at the position where the punching process is performed, and is preferably based on the orientation axis at the center position of the substantially square shape after the punching process.

The punching angle from the protective film original fabric is the angle formed by the stretching direction in the width direction of the biaxially stretched polyethylene resin film of the protective film raw material and one side of the substantially rectangular shape to be punched. The punching is preferably ± 25 ° of the optimum punching angle α represented by the formula (1), more preferably α ± 15 °, and most preferably within α ± 5 °.
α = − [(φ−45 °) −γ] + (90 ° × n) (1)
(In the formula (1), φ is an angle formed by the horizontal axis of the image display unit and the polarization axis of linearly polarized light emitted from the image display unit, and γ is a biaxially stretched polyethylene-based protective film raw material. The angle formed by the stretching direction in the width direction of the resin film and the orientation axis of molecules in the width direction of the polyethylene-based resin film of the original protective film, n is an integer of −3 to 3.)

  Here, the horizontal axis of the image display unit indicates the horizontal axis when the image display unit is viewed when the image is displayed. When the image display unit has a substantially square shape, the upper side or the lower side thereof A parallel axis. 5A or 5B, the angle φ formed by the horizontal axis 22 of the image display unit 21 and the polarization axis 23 of the linearly polarized light emitted from the image display unit is the image display unit. Is an angle in the counterclockwise direction from the horizontal axis of the image display unit to the polarization axis of the linearly polarized light, and 0 ° ≦ φ ≦ 180 °.

  The angle γ between the stretching direction in the width direction of the biaxially stretched polyethylene resin film of the original protective film and the molecular orientation axis in the width direction in the polyethylene resin film of the protective film original is the polyethylene resin. It is a shift angle of molecules with respect to the stretching direction in the width direction of the film. Since γ is a shift angle, as shown in FIG. 6, from the stretching direction 12 in the width direction of the polyethylene resin film to the molecular orientation axis 13 in the width direction of the polyethylene resin film at an arbitrary point. The counterclockwise angle (γ1) is a positive angle, and the clockwise angle (γ2) from the stretching direction 12 in the width direction of the film to the molecular orientation axis 13 in the width direction of the polyethylene resin film at an arbitrary point. ) Is a negative angle. Generally, since the angle between the width direction and the alignment axis in the width direction is within 45 °, it can be expressed as −45 ° ≦ γ ≦ 0 ° or 0 ° ≦ γ ≦ 45 °.

  When the protective film punched at the above-mentioned punching angle is applied to an image display device having an image display module and a transparent panel provided on the top of the image display module, the transparent panel on the image display module side It is installed on the surface opposite to the surface so that the surface of the punched protective film is a surface layer. Moreover, when applying the said protective film to the surface at the side of the image display module of a transparent panel, what is necessary is just to install so that the back surface side of the cut-out protective film may become a table | surface.

Use a protective film with selectivity on the front and back, such as a protective film with a hard coat layer or adhesive layer, and attach the protective film to the image display module side of the transparent panel so that the surface side of the protective film is the front layer. In the embodiment provided in the above, the angle formed by the stretching direction in the width direction of the biaxially stretched polyethylene resin film of the original film of the protective film and one side of the substantially rectangular shape to be punched is expressed by the following formula (2): The punching is preferably performed at a punching angle of ± 25 ° of the optimum punching angle β represented.
β = [(φ−45 °) + γ] + (90 ° × n) (2)
(In the formula (2), φ is an angle formed by the horizontal axis of the image display unit and the polarization axis of linearly polarized light emitted from the image display unit, and γ is a biaxially stretched polyethylene-based protective film raw material. The angle formed by the width direction of the resin film and the orientation axis in the width direction in the polyethylene-based resin film of the protective film raw material, n is an integer of -3 to 3.) The punching angle β ± 15 ° is more preferable, and it is most preferably within ± 5 °.

  The optimum punching angles α and β are, as shown in FIG. 7, the stretching direction 12 in the width direction of the biaxially stretched polyethylene resin film of the original film 10 of the protective film and the substantially rectangular shape to be punched. Of the angle formed with one side of the protective film 14, the counterclockwise angle (α1) from the stretching direction in the width direction of the film to one side of the substantially rectangular protective film 14 to be punched is defined as a positive angle. A clockwise angle from the width direction to one side of the substantially rectangular protective film 15 to be punched is defined as a negative angle (α2). (In FIG. 7, α1 and α2 are shown with reference to the lines parallel to the sides passing through the center point of the substantially rectangular protective film.) One side of the substantially square shape to be punched is an arbitrary side. Although it may be, it is preferable to use the side which becomes the side of the image display visually recognized when provided in the image display unit of the image display device as a reference. Further, it is preferable to perform the punching process so that the center point of the substantially square shape to be punched coincides with the point for confirming the orientation axis in the width direction of the polyethylene-based resin film because the punching process can be performed with high accuracy.

  The angle γ of the orientation axis in the width direction of the protective film raw material in the present invention, the punching angles α, β are angles when the protective film raw material is viewed from the surface side, for example, a protective film having an adhesive layer on one side If so, it means the angle when the film is viewed from the side opposite to the pressure-sensitive adhesive layer.

  In addition, in the process of punching the original film of the protective film to obtain a substantially rectangular protective film, the stretching direction in the width direction of the biaxially stretched polyethylene resin film in the original film of the protective film, Since the effect of the present invention is particularly high, it is preferable to perform the punching process of the substantially square shape at an angle other than the range of −5 ° to 5 ° with respect to the side of the substantially square shape to be processed.

  The punching process into a substantially square shape may be any punching process such as a punching process with a substantially square-shaped punching blade having a desired size or a laser punching process. Among these, the punching with the punching blade is preferable because it is easy to adjust the angle of the punching blade.

  The size of the protective film that is punched into a substantially square shape may be appropriately adjusted according to the size suitable for the image display unit of the image display device to be applied. It is preferable that the size is suitable for a portable electronic device having an image display unit of 5 to 16 inches, preferably 3.5 to 12.1 inches. The size of the protective film suitable for the portable electronic device is preferably 3.5 to 16 inches diagonal, more preferably 3.5 to 12.1 inches.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these.

[Preparation of hard coating agent]
<Synthesis of urethane acrylate>
In a flask equipped with a stirrer, a gas introduction tube, a cooling tube, and a thermometer, 254 parts by weight of butyl acetate, 222 parts by weight of isophorone diisocyanate (hereinafter referred to as “IPDI”), 0.5 part by weight of p-methoxyphenol, dibutyl After charging 0.5 parts by weight of tin diacetate and raising the temperature to 70 ° C., a mixture of pentaerythritol triacrylate (hereinafter referred to as “PE3A”) / pentaerythritol tetraacrylate (hereinafter referred to as “PE4A”) (weight ratio). 75/25 mixture) 795 parts by weight were added dropwise over 1 hour. After completion of the dropwise addition, the mixture is reacted at 70 ° C. for 3 hours, and further reacted until the infrared absorption spectrum of 2250 cm −1 indicating an isocyanate group disappears, and a urethane acrylate (UA1) / PE4A mixture (a mixture of 80/20 by weight, non-volatile) 80% by weight butyl acetate solution). The molecular weight of urethane acrylate (UA1) was 818.

<Synthesis of polymer>
In a flask equipped with a stirrer, a gas introduction pipe, a cooling pipe, and a thermometer, 250 parts by weight of glycidyl methacrylate (hereinafter referred to as “GMA”), 1.3 parts by weight of lauryl mercaptan, and methyl isobutyl ketone (hereinafter referred to as “MIBK”). 1000 parts by weight and 7.5 parts by weight of 2,2′-azobisisobutyronitrile (hereinafter referred to as “AIBN”) were charged and the mixture was stirred at 90 ° C. over 1 hour while stirring under a nitrogen stream. The temperature was raised and reacted at 90 ° C. for 1 hour. Next, a mixture of 750 parts by weight of GMA, 3.7 parts by weight of lauryl mercaptan, and 22.5 parts by weight of AIBN was added dropwise over 2 hours while stirring at 90 ° C., followed by reaction at 100 ° C. for 3 hours. Thereafter, 10 parts by weight of AIBN was charged and further reacted at 100 ° C. for 1 hour, and then heated to around 120 ° C. and reacted for 2 hours. Cool to 60 ° C., replace the nitrogen inlet tube with an air inlet tube, add 507 parts by weight of acrylic acid (hereinafter referred to as “AA”), 2 parts by weight of p-methoxyphenol, and 5.4 parts by weight of triphenylphosphine. After mixing, the reaction solution was bubbled with air, heated to 110 ° C., and reacted for 8 hours. Thereafter, 1.4 parts by weight of p-methoxyphenol was added, and after cooling to room temperature, MIBK was added so that the nonvolatile content was 50% by weight, and the above polymer (MIBK solution having a nonvolatile content of 50% by weight) was obtained. . In addition, the weight average molecular weight of the obtained polymer was 31,000 (in terms of polystyrene by GPC), and the (meth) acryloyl group equivalent was 300 g / eq.

  3.1 parts by weight of ethyl acetate, 40.0 parts by weight of a butyl acetate solution (non-volatile content 80%) of a urethane acrylate (UA1) / PE4A mixture (a mixture of 80/20 by weight), a MIBK solution (non-volatile content) of the above polymer 50%) 64.0 parts by weight, dipentaerythritol hexaacrylate (hereinafter referred to as “DPHA”) 16.0 parts by weight, photoinitiator 1-hydroxycyclohexyl phenyl ketone (hereinafter referred to as “HCPK”) 1.63 1 part by weight, 1.16 parts by weight of photoinitiator diphenyl-2,4,6-trimethylbenzoylphosphine oxide (hereinafter referred to as “TPO”) are uniformly mixed to prepare a resin composition (non-volatile content: 65%). did.

<Adjustment of hard coating agent>
100 parts by weight of a MIBK solution (non-volatile content: 50% by weight) of the resin composition prepared by the above method and 2 parts by weight of a reactive fluorine antifouling agent (OPTOOL DAC; manufactured by Daikin Industries, Ltd., non-volatile content: 20% by weight) After mixing, the hard coating agent (A) was obtained by diluting with ethyl acetate such that the nonvolatile content was 40% by weight.

[Preparation of pressure-sensitive adhesive composition]
<Preparation of acrylic copolymer, etc.>
Preparation of acrylic copolymer In a reaction vessel equipped with a stirrer, reflux condenser, thermometer, dropping funnel and nitrogen gas inlet, 85 parts by weight of butyl acrylate, 15 parts by weight of methyl methacrylate, 4 parts by weight of acrylic acid, dimethylaminoethyl 1 part by mass of acrylate was dissolved in ethyl acetate and polymerized to obtain an acrylic copolymer (1) having a mass average molecular weight (Mw) of 700,000 (solid content 25%).

<Adjustment of pressure-sensitive adhesive composition>
To 100 parts by mass of the acrylic copolymer (1), 0.60 part by mass of an epoxy-based crosslinking agent (E-2XM solid content 2%, manufactured by Soken Chemical Co., Ltd.) is added, and the mixture is stirred with a stirrer for 20 minutes. (A) was obtained.

[Preparation of the original protective film]
Using the hard coat agent (A) and the pressure-sensitive adhesive composition (a), a protective film original fabric was prepared as follows.

<Preparation of protective film original fabric A>
On one side of a 100 μm-thick biaxially stretched polyethylene terephthalate film (Cosmo Shine A4100 manufactured by Toyobo Co., Ltd.) having an angle γ of −30 ° formed by the width direction of the original film and the orientation axis in the width direction in the film, After applying the hard coating agent (A) prepared above and drying at 60 ° C. for 90 seconds, an ultraviolet irradiation apparatus (“F450” manufactured by Fusion UV Systems Japan Co., Ltd., lamp: 120 W / cm, H bulb) ) Was used to irradiate ultraviolet rays at an irradiation light amount of 0.5 J / cm ² to form a hard coat layer having a thickness of 10 μm. Next, the pressure-sensitive adhesive (a) was applied to the surface of the hard coat film opposite to the hard coat layer so that the thickness of the pressure-sensitive adhesive layer after drying was 10 μm, and dried at 85 ° C. for 2 minutes. A 38 μm thick polyester film (hereinafter referred to as # 38 release film) having one side peeled off with a silicone compound was bonded to the obtained pressure-sensitive adhesive layer surface, and aged at 40 ° C. for 2 days to produce a protective film original fabric A having a total thickness of 158 μm. Obtained.

<Preparation of protective film original fabric B>
On one side of a 100 μm-thick biaxially stretched polyethylene terephthalate film (Cosmo Shine A4100 manufactured by Toyobo Co., Ltd.) having an angle γ of 0 ° between the width direction of the original film and the orientation axis in the width direction in the film, After applying the hard coating agent (A) prepared in step 1 and drying at 60 ° C. for 90 seconds, an ultraviolet irradiation device in an air atmosphere (“F450” manufactured by Fusion UV Systems Japan Co., Ltd., lamp: 120 W / cm, H bulb) Was used to irradiate ultraviolet rays at an irradiation light amount of 0.5 J / cm ² to form a hard coat layer having a thickness of 10 μm. Next, the pressure-sensitive adhesive (a) was applied to the surface of the hard coat film opposite to the hard coat layer so that the thickness of the pressure-sensitive adhesive layer after drying was 10 μm, and dried at 85 ° C. for 2 minutes. A 38 μm thick polyester film (hereinafter referred to as # 38 release film), one side of which was peeled off with a silicone compound, was bonded to the surface of the obtained pressure-sensitive adhesive layer and aged at 40 ° C. for 2 days to produce a protective film original fabric B having a total thickness of 158 μm. Obtained.

<Preparation of protective film C>
On one side of a 100 μm-thick biaxially stretched polyethylene terephthalate film (Cosmo Shine A4100 manufactured by Toyobo Co., Ltd.) having an angle γ of 20 ° formed by the width direction of the original film and the orientation axis in the width direction in the film, After applying the hard coating agent (A) prepared in step 1 and drying at 60 ° C. for 90 seconds, an ultraviolet irradiation device in an air atmosphere (“F450” manufactured by Fusion UV Systems Japan Co., Ltd., lamp: 120 W / cm, H bulb) Was used to irradiate ultraviolet rays at an irradiation light amount of 0.5 J / cm ² to form a hard coat layer having a thickness of 10 μm. Next, the pressure-sensitive adhesive (a) was applied to the surface of the hard coat film opposite to the hard coat layer so that the thickness of the pressure-sensitive adhesive layer after drying was 10 μm, and dried at 85 ° C. for 2 minutes. A 38 μm thick polyester film (hereinafter referred to as # 38 release film) having one surface peeled with a silicone compound was bonded to the obtained pressure-sensitive adhesive layer surface, and aged at 40 ° C. for 2 days to produce a protective film original fabric C having a total thickness of 158 μm. Obtained.

<Preparation of protective film original fabric D>
On one side of a 100 μm-thick biaxially stretched polyethylene naphthalate film (Teonex manufactured by Teijin DuPont) with an angle γ formed by the width direction of the original film and the orientation axis in the width direction of the film being 0 °, After applying the hard coating agent (A) prepared in step 1 and drying at 60 ° C. for 90 seconds, an ultraviolet irradiation device in an air atmosphere (“F450” manufactured by Fusion UV Systems Japan Co., Ltd., lamp: 120 W / cm, H bulb) Was used to irradiate ultraviolet rays at an irradiation light amount of 0.5 J / cm ² to form a hard coat layer having a thickness of 10 μm. Next, the pressure-sensitive adhesive (a) was applied to the surface of the hard coat film opposite to the hard coat layer so that the thickness of the pressure-sensitive adhesive layer after drying was 10 μm, and dried at 85 ° C. for 2 minutes. A 38 μm thick polyester film (hereinafter referred to as # 38 release film) having one surface peel-treated with a silicone compound was bonded to the obtained pressure-sensitive adhesive layer surface, and aged at 40 ° C. for 2 days to form a protective film original fabric D having a total thickness of 158 μm. Obtained.

<Preparation of protective film original fabric E>
The hard coating agent (A) prepared above was applied to one side of a 125 μm thick unstretched acrylic film (Acryprene manufactured by Mitsubishi Rayon Co., Ltd.), dried at 60 ° C. for 90 seconds, and then irradiated with an ultraviolet irradiation device (fusion) in an air atmosphere. Using a “F450” manufactured by UV Systems Japan, Inc., a lamp: 120 W / cm, an H bulb, ultraviolet rays were irradiated at an irradiation light amount of 0.5 J / cm ² to form a hard coat layer having a thickness of 10 μm. Next, the pressure-sensitive adhesive (a) was applied to the surface of the hard coat film opposite to the hard coat layer so that the thickness of the pressure-sensitive adhesive layer after drying was 10 μm, and dried at 85 ° C. for 2 minutes. A 38 μm thick polyester film (hereinafter referred to as # 38 release film) having one surface peeled off with a silicone compound was bonded to the obtained pressure-sensitive adhesive layer surface, and aged at 40 ° C. for 2 days to produce a protective film original fabric E having a total thickness of 183 μm. Obtained.

[Protective film punching and bonding to image display device]
Using the above protective film original fabric, a protective film was produced as follows and bonded to an image display device.

<Example 1>
The protective film original fabric A was punched so that the film punching angle was −10 ° to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 0 ° were fixed so that the protective film was positioned on the top.

<Example 2>
The protective film original fabric A was punched so that the punching angle was 0 ° to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 0 ° were fixed so that the protective film was positioned on the top.

<Example 3>
The protective film original fabric A was punched so that the punching angle was 15 ° to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 0 ° were fixed so that the protective film was positioned on the top.

<Example 4>
The protective film original fabric A was punched so that the punching angle was 30 ° to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 0 ° were fixed so that the protective film was positioned on the top.

<Example 5>
The protective film original fabric A was punched so that the punching angle was 40 ° to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 0 ° were fixed so that the protective film was positioned on the top.

<Example 6>
The protective film original fabric B was punched so that the punching angle was 45 ° to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 0 ° were fixed so that the protective film was positioned on the top.

<Example 7>
The protective film original fabric C was punched so that the punching angle was 65 ° to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 0 ° were fixed so that the protective film was positioned on the top.

<Example 8>
The protective film original fabric A was punched so that the punching angle was −15 ° to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 30 ° were fixed so that the protective film was positioned on the top.

<Example 9>
The protective film original fabric B was punched so that the punching angle was 15 ° to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 30 ° were fixed so that the protective film was positioned on the top.

<Example 10>
The protective film original fabric C was punched so that the punching angle was 35 ° to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 30 ° were fixed so that the protective film was positioned on the top.

<Example 11>
The protective film original fabric A was punched so that the punching angle was 35 ° to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 160 ° were fixed so that the protective film was positioned on the top.

<Example 12>
The protective film original fabric B was punched so that the punching angle was 65 ° to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 160 ° were fixed so that the protective film was positioned on the top.

<Example 13>
The protective film original fabric C was punched so that the punching angle was 85 ° to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 160 ° were fixed so that the protective film was positioned on the top.

<Example 14>
The protective film original fabric D was punched so that the punching angle was 20 ° to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 0 ° were fixed so that the protective film was positioned on the top.

<Example 15>
The protective film original fabric D was punched so that the punching angle was 45 ° to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 0 ° were fixed so that the protective film was positioned on the top.

<Example 16>
The protective film original fabric D was punched so that the punching angle was 65 ° to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 0 ° were fixed so that the protective film was positioned on the top.

<Comparative Example 1>
The protective film original fabric A was punched so that the punching angle was −30 ° to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 0 ° were fixed so that the protective film was positioned on the top.

<Comparative example 2>
The protective film original fabric A was punched so that the punching angle was −20 ° to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 0 ° were fixed so that the protective film was positioned on the top.

<Comparative Example 3>
The protective film original fabric A was punched so that the punching angle was 50 ° to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 0 ° were fixed so that the protective film was positioned on the top.

<Comparative example 4>
The protective film original fabric A was punched so that the punching angle was 65 ° to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 0 ° were fixed so that the protective film was positioned on the top.

<Comparative Example 5>
The protective film original fabric D was punched so that the punching angle was 0 ° to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 0 ° were fixed so that the protective film was positioned on the top.

<Comparative Example 6>
The protective film original fabric D was punched so that the punching angle was 90 ° to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 0 ° were fixed so that the protective film was positioned on the top.

<Comparative Example 7>
The protective film original fabric E was punched so that the punching angles were 0, 20, 45, 70, and 90 ° to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 0 ° were fixed so that the protective film was positioned on the top.

<Comparative Example 8>
The protective film original fabric E was punched so that the punching angles were 0, −20, −45, −70, and −90 ° to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 0 ° were fixed so that the protective film was positioned on the top.

<Comparative Example 9>
The protective film original fabric E was punched out so that the punching angle was 0, 20, 45, 70, 90 ° clockwise to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 30 ° were fixed so that the protective film was positioned on the top.

<Comparative Example 10>
The protective film original fabric E was punched so that the punching angle was 0, −20, −45, −70, and −90 ° counterclockwise to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 30 ° were fixed so that the protective film was positioned on the top.

<Comparative Example 11>
The protective film original fabric E was punched out so that the punching angle was 0, 20, 45, 70, 90 ° clockwise to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 160 ° were fixed so that the protective film was positioned on the top.

<Comparative Example 12>
The protective film original fabric E was punched so that the punching angle was 0, −20, −45, −70, and −90 ° counterclockwise to obtain a protective film. This protective film was bonded to one surface of a transparent rectangular glass panel, and the glass panel and a liquid crystal module having a polarization axis angle φ of 160 ° were fixed so that the protective film was positioned on the top.

<Comparative Example 13>
The glass panel alone and the liquid crystal module having a polarization axis angle φ of 0 ° were fixed so that the protective film was positioned at the top.

  The image display devices obtained in the above examples and comparative examples were evaluated as follows. The obtained result is shown to Tables 1-2.

[Verification of image visibility]
A polarizing plate that transmits only linearly polarized light orthogonal to the linearly polarized light emitted from the liquid crystal module was installed on the upper part of the image display devices manufactured in the above-described examples and comparative examples. The polarizing plate was rotated 360 °, and the visibility of the image emitted from the image display device was confirmed (FIG. 8). The evaluation criteria were as follows. The evaluation results are shown in Tables 4-6. Further, FIG. 9 shows the result of confirming the visibility of the image display device of Example 1, FIG. 10 shows the result of confirming the visibility in the region where the luminance is lowered in the image display device of Example 3, and Comparative Example 1 FIG. 11 shows the result of confirming the visibility in the area where the image becomes dark in the image display apparatus of FIG. The cursors in FIGS. 9 to 11 are images on the image display unit.
A: The luminance does not change over the entire rotation region, has very good luminance, and the image visibility is very good over the entire rotation region.
A: The luminance hardly changes in the entire rotation range, has a good luminance, and the image visibility in the entire rotation range is good.
(Triangle | delta): There exists an area | region where a brightness | luminance falls in a part of rotation area, and although it feels a little dark in the said area | region, it has image visibility which can be used in the whole rotation area.
X: The image becomes dark in a part of the rotation region, and the image is hardly visible in the region.

[Glass panel scattering prevention]
The evaluation of the glass scattering prevention property was performed based on the three-point bending test method of JIS R1601 standard. The surface on the protective film side of the glass panel (Comparative Example 13 is a glass panel without a protective film) on which the protective film of the image display device produced in the above Examples and Comparative Examples was bonded was fixed at two points. Next, stress was applied to the center of the glass panel side, and the degree of scattering of the glass was confirmed when the glass was broken. The evaluation criteria for glass scattering were as follows.
○: No glass fragments scattered ×: Glass fragments scattered

[Measurement of surface pencil hardness]
The release film of the protective film obtained in the above Examples and Comparative Examples was peeled off and attached to a glass plate. The pencil hardness of the hard coat layer surface was measured using a pencil scratch tester (manual type) for coating film manufactured by Imoto Seisakusho Co., Ltd. based on the provisions of JIS K 5600-5-4 (1999 edition). The evaluation criteria were as follows.
○: A scratch with a pencil of hardness H △: A scratch with a pencil of hardness F ×: A scratch with a pencil of hardness F

[Measurement of total light transmittance and haze]
The protective film was affixed to a glass plate having a thickness of 0.5 mm, a length of 50 mm, and a width of 40 mm, and then fixed by performing heat and pressure treatment at 5 atm, 50 ° C. for 20 minutes. The total light transmittance and haze were measured based on JIS K7105 and JIS K7136 of the sample using “HR-100 type” manufactured by Murakami Color Research Laboratory.

  As apparent from Tables 1 to 4, the protective film produced by the production method of the present invention was able to realize suitable visibility while having good protective performance as a protective film.

DESCRIPTION OF SYMBOLS 1 Image display module 2 Transparent panel 3 Linearly polarized light radiate | emitted from an image display module 4 Image display surface surface 5 Polarization direction of linearly polarized light 6 One orientation axis direction of the base material layer of a protective film 7 The other of the base material layer of a protective film Alignment axis direction 10 Protective film raw fabric 11 Biaxially stretched polyethylene resin film flow direction stretch direction 12 Biaxially stretched polyethylene resin film width direction stretch direction 13 Biaxially stretched polyethylene resin film molecule width Directional orientation axis 14 Protective film having a substantially rectangular shape to be punched 21 Image display unit 22 Horizontal axis of image display unit 23 Polarization axis of linearly polarized light emitted from the image display unit 31 Liquid crystal module emitting linearly polarized light 32 Protective film 33 Transparent glass panel 34 Polarizing plate

Claims (6)

An image display device having an image display module in which light emitted from an image display unit is linearly polarized light and a transparent panel provided on the image display module, and manufacturing a protective film to be attached to at least one surface of the transparent panel A way to
The protective film is a protective film having a film base layer made of a biaxially stretched polyethylene resin film,
The process of punching the original film of the protective film to obtain a substantially rectangular protective film,
When the transparent panel with the protective film attached to the upper part of the image display module is provided in the substantially rectangular shape, the polarization axis of linearly polarized light emitted from the image display unit, and the film base layer The angle θ1 formed by one of the alignment axes of the molecules of the film and the angle θ2 formed by the polarization axis of the linearly polarized light emitted from the image display unit and the other alignment axis of the molecules of the film base material layer are 20 to 70 °. The manufacturing method of the protective film characterized by being the punching process which becomes. In an image display device having an image display module in which light emitted from an image display unit is linearly polarized light and a transparent panel provided on an upper portion of the image display module, the transparent panel is pasted on the opposite surface of the image display module. A method for producing a protective film, comprising:
The protective film is a protective film having a film base layer made of a biaxially stretched polyethylene resin film,
The process of punching the original film of the protective film to obtain a substantially rectangular protective film,
The angle between the stretching direction in the width direction of the biaxially stretched polyethylene resin film of the original film of the protective film and the side of the substantially rectangular shape to be punched is the following formula: A manufacturing method of a protective film, characterized by being a punching process at a punching angle of ± 25 ° of the angle α represented by (1).
α = − [(φ−45 °) −γ] + (90 ° × n) (1)
(In the formula (1), φ is an angle formed by the horizontal axis of the image display unit and the polarization axis of linearly polarized light emitted from the image display unit, and γ is a biaxially stretched polyethylene-based protective film raw material. The angle formed by the width direction of the resin film and the orientation axis in the width direction in the polyethylene resin film of the original protective film, n is an integer of −3 to 3.) In an image display device having an image display module in which light emitted from the image display unit is linearly polarized light and a transparent panel provided on the image display module, a protective film to be attached to the image display module surface of the transparent panel A method of manufacturing
The protective film is a protective film having a film base layer made of a biaxially stretched polyethylene resin film,
The process of punching the original film of the protective film to obtain a substantially rectangular protective film,
The angle between the stretching direction in the width direction of the biaxially stretched polyethylene resin film of the original film of the protective film and the side of the substantially rectangular shape to be punched is the following formula: A method for producing a protective film, characterized by being a punching process at a punching angle of ± 25 ° of the angle β represented by (1).
β = [(φ−45 °) + γ] + (90 ° × n) (2)
(In the formula (1), φ is an angle formed by the horizontal axis of the image display unit and the polarization axis of linearly polarized light emitted from the image display unit, and γ is a biaxially stretched polyethylene-based protective film raw material. The angle formed by the width direction of the resin film and the orientation axis in the width direction in the polyethylene resin film of the original protective film, n is an integer of −3 to 3.)   The manufacturing method of the protective film in any one of Claims 1-3 in which the raw material of the said protective film has an adhesive layer in at least one surface of the film base material layer which consists of a biaxially stretched polyethylene-type resin film.   The manufacturing method of the protective film in any one of Claims 1-4 in which the raw material of the said protective film has a hard-coat layer in at least one surface of the film base material layer which consists of a biaxially stretched polyethylene-type resin film.   The protective film obtained by the manufacturing method in any one of Claims 1-5.